How can the speech of an autistic child be improved?

Q:My 13 years old niece is autistic and goes to a special school. She speaks only words and not sentences. She was diagnosed autistic at the age of 3.5 years and she started regressing herself, which went unnoticed unfortunately. Ever since her condition has been diagnosed, her parents started taking her to speech therapist. Currently, she is not being taken for speech therapy as her school is providing the facility. She used to be very hyper active and has an intelligence quotient far beyond her age. Does she require an independent speech therapist after her school hours? Also, does she need to have special dietary habits? What all tests does she need to undergo to find out if she is allergic to any particular food item? How can her parents make her life simple and easier?

A:There seems to be no need to test the child for allergy, when she has not shown any signs of being allergic to food etc. We should aim to minimise the need for experts and increase the role of friends and family to take over the task of helping her.
Since the school is satisfactory and gives her speech therapy and she is showing improvement, what is the need for more hours of therapy? More is not always better!
The parents and other family members should spend her playtime with her and let her speech improve in the course of the game. You should see what she likes to do and what she is good at and then provide opportunities for her to express herself.